U.S. Pat. No. 3,842,194 to Clemens describes a video recording and playback system whereby conductive disc replicas can be prepared having geometric variations in the bottom of a spiral groove in the disc surface which is representative of video information. The conductive discs are coated with a thin dielectric coating. During playback, a metal stylus, riding upon the dielectric coating, detects the dimensional variations in the groove as capacitance variations which can be electrically processed to recreate electrical signals representative of the recorded video information.
U.S. Pat. No. 3,843,399 discloses one method of applying the dielectric coating. According to this method, a thin, uniform, conformal dielectric film is applied by a glow discharge technique in a vacuum chamber. Small amounts of a dielectric or dielectric polymer precursor are fed to the chamber and a potential is applied so as to cause a glow in the chamber in the vicinity of the disc, in turn causing a dielectric film to form on the disc. When styrene is employed as the film-former, a tough, adherent coating of a polymer of styrene forms on the disc.
The dielectric in turn can be coated with a lubricant film to further improve the playback quality of the disc. Lubricant films of methyl alkyl siloxanes are disclosed in U.S. Pat. No. 3,833,408.
Although the above method is rapid and good quality films are obtained which have good wear properties, it has been found that these films deteriorate on standing. Thus, although a styrene polymer film on a video disc can be played back from 50-100 times without noticeable deterioration shortly after fabrication, upon standing for 1 to 3 months, the films deteriorate so that after only 10 to 20 plays the record wear becomes apparent. Thus it is desired to improve the long-term resistance of such dielectric films to deterioration.